JP2011026455A - Hot melt type adhesive composition and warm temperature material provided with the adhesive composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hot melt type adhesive composition which, when used as an adhesive of a warm temperature material, shows few differences of adhesive strength, is suppressed in reduction of adhesive strength even after repeated adhesion, and does not produces a paste residue to an adherend, and which can be produced inexpensively. <P>SOLUTION: In a hot melt type adhesive, a tackifier is blended with a styrenic thermoplastic elastomer, and the tackifier at least includes a styrenic resin and a petroleum-based resin or a terpene-based resin, the component ratio thereof being in the range of 1/9 to 3/7. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hot-melt pressure-sensitive adhesive composition, and more particularly, an adhesive member for sticking and fixing a disposable warmer having a thermal effect to an adherend, which has adhesiveness and removability during heating. The present invention relates to a hot-melt pressure-sensitive adhesive composition that can form a well-balanced pressure-sensitive adhesive layer.

  Conventional adhesives and adhesive films for heating materials that give a thermal effect have drawbacks such as difficulty in peeling when peeled after heat generation, adhesive remains on clothing, and damage to clothing.

In order to solve these drawbacks, a pressure-sensitive adhesive composed of a specific radial block copolymer mainly composed of a vinyl aromatic compound and a conjugated diene compound has been proposed. (Patent Document 1)

  Also, with respect to this Patent Document 1, there is little fluctuation in the adhesive force with respect to the temperature change of the thermal material giving a thermal effect, the adhesive has sufficient adhesive force before heat generation and during use, and is easy to peel off after use. There is an invention of an agent and a thermal material using the same. This invention comprises (1) an aromatic vinyl monomer and an alkyl or alkenyl (meth) acrylate having an alkyl group or alkenyl group having 4 to 24 carbon atoms. A copolymer (A) as a monomer, and (2) a (co) polymer (B) having a glass transition temperature higher by 10 ° C. or more than A and having an aromatic vinyl monomer as an essential constituent monomer A pressure-sensitive adhesive characterized by the above has been proposed. (Patent Document 2)

JP-A-7-8517

JP2008-184612

  In the pressure-sensitive adhesive composition described in Patent Document 1, as pointed out in Patent Document 2, the adhesive force after heat generation (50 to 60 ° C.) is lowered, and there is a problem that the thermal material slides down.

  Moreover, in the said patent document 2, there is little fluctuation | variation of the adhesive force with respect to the temperature change of a thermal material, it has sufficient adhesive force before heat_generation | fever and during use, and also the adhesive for thermal materials which is easy to peel off after use. It is the feature and the problem of patent document 1 is improved.

  However, in Patent Document 2, (1) a copolymer (A) having an aromatic vinyl monomer and an alkyl or alkenyl (meth) acrylate having an alkyl group or alkenyl group having 4 to 24 carbon atoms as essential constituent monomers, And (2) a pressure-sensitive adhesive comprising a (co) polymer (B) having a glass transition temperature higher than that of A by 10 ° C. or more and having an aromatic vinyl monomer as an essential constituent monomer. The number of steps for producing the monomers (1) and (2) is increased, resulting in inconvenience in proposing a hot melt pressure-sensitive adhesive at low cost. Furthermore, the above-mentioned conventional pressure-sensitive adhesive has a problem that the adhesive strength is significantly reduced when the bonding to the adherend is repeated several times.

  The present invention uses a known production technique and commercially available raw materials, and maintains the balance between adhesive force and cohesive force by making the constituent materials of the pressure-sensitive adhesive composition and the proportion blend thereof in a specific range, and changes the temperature of the thermal material. The adhesive strength is less fluctuating than before, has sufficient adhesive strength before heat generation and during use, and is easy to peel off after use. It aims at providing the hot-melt-type adhesive composition which can be suppressed, and a thermal material using the same.

  The hot-melt pressure-sensitive adhesive composition of the present invention is a hot-melt pressure-sensitive adhesive composition obtained by blending a tackifying resin with a styrene-based thermoplastic elastomer, wherein the tackifying resin is at least styrene. The softening point is 150 ° C. or higher (A) with a resin and the composition ratio of A / B is 1/9 to 3/7, including a softening point 120 to 140 ° C. (B) with a petroleum resin and / or a terpene resin. It is characterized by being within.

  The hot-melt pressure-sensitive adhesive composition of the present invention is composed of 25 to 45 parts by weight of the styrenic thermoplastic elastomer and 35 to 65 parts by weight of the tackifying resin, and 1 to 25 parts by weight. Part of the plasticizer is contained.

  Furthermore, the thermal material of the present invention is characterized by comprising the above-described hot-melt adhesive composition.

  According to the hot melt pressure-sensitive adhesive composition of the present invention, by using the raw materials and the blending ratio thereof as described above, for example, when used as a pressure-sensitive adhesive for a thermal material, before heat generation (use) and heat generation (use) The difference in the subsequent adhesive force is small, and it can be easily adhered to the adherend and easily peeled off. Moreover, even if it adheres repeatedly, the fall of adhesive force is suppressed.

  Moreover, even if it repeats bonding several times, the fall of adhesive force is suppressed compared with the past. Furthermore, it can be manufactured at low cost using known manufacturing techniques and commercially available raw materials.

  Moreover, the thermal material provided with the hot melt pressure-sensitive adhesive composition of the present invention can be easily peeled without damaging the underwear.

  The hot melt pressure-sensitive adhesive composition of the present invention is suitable for sticking and fixing a thermal material such as a disposable body warmer to an adherend, and includes a styrene-based thermoplastic elastomer, a tackifying resin, and a plasticizer, In the range which does not impair the above, inorganic fillers, surfactants, coupling agents, antioxidants, ultraviolet absorbers, light stabilizers, colorants and the like can be added as necessary.

  Styrenic thermoplastic elastomer is a thermoplastic elastomer having rubber elasticity, and is blended as a main constituent material of a hot-melt pressure-sensitive adhesive composition. This styrenic thermoplastic elastomer acts to impart cohesive force and flexibility to the pressure-sensitive adhesive composition.

  As the styrenic thermoplastic elastomer, a polystyrene block-polyolefin block copolymer or a hydrogenated polystyrene block-polyolefin block copolymer can be used. Specifically, a styrene-isoprene-styrene block copolymer (hereinafter abbreviated as SIS), a styrene-butadiene-styrene block copolymer (hereinafter abbreviated as SBS), a styrene-isobutylene-styrene block copolymer (hereinafter referred to as SIBS). Styrene-ethylene-propylene-styrene block copolymer (hereinafter abbreviated as SEPS), styrene-ethylene-butylene-styrene block copolymer (hereinafter abbreviated as SEBS), An ethylene-ethylene / propylene styrene block copolymer (hereinafter abbreviated as SEEPS) and the like. As the styrenic thermoplastic elastomer, one or more of these may be mixed and used.

  These styrenic thermoplastic elastomers are appropriately selected according to the properties required for the hot melt pressure-sensitive adhesive composition. For example, SIS is preferably used to increase the adhesive strength and tack of the pressure-sensitive adhesive composition, SBS is preferably used to increase the heat resistance of the pressure-sensitive adhesive composition, and the stability of the pressure-sensitive adhesive composition is increased. For this, SEPS and SEBS are preferably used.

  The styrene content in the styrenic thermoplastic elastomer is 10 to 16% by weight, more preferably 12 to 15% by weight.

When the styrene content in the styrene-based thermoplastic elastomer is less than 10% by weight, the heat resistance is lowered, and the adhesive paste remains after the heating of the thermal material. When the styrene content exceeds 30% by weight, the tackiness and the low temperature property are lowered, and the thermal material slips.

  The melt flow rate (MFR) of the styrene-based thermoplastic elastomer is preferably in the range of 5 (g / 10 min) to 35 (g / 10 min) under the G condition (200 ° C./5 kg). If the MFR of the styrene-based thermoplastic elastomer is less than 5 (g / 10 minutes), there is a problem that the melt viscosity of the hot melt pressure-sensitive adhesive is increased and the coating property is deteriorated. Moreover, when MFR of a styrene-type thermoplastic elastomer exceeds 35 (g / 10min), there exists a malfunction that heat resistance is insufficient.

  The blending amount of the styrenic thermoplastic elastomer for producing the hot melt pressure-sensitive adhesive composition of the present invention is 25 parts by weight or more and 45 parts by weight or less, preferably 30 parts by weight or more and 35 parts by weight or less. When the blending amount of the styrenic thermoplastic elastomer is less than 25 parts by weight, the cohesive force of the hot melt pressure-sensitive adhesive is likely to be reduced and the tackiness is also poor. On the other hand, when it exceeds 45 parts by weight, the melt viscosity of the hot melt pressure-sensitive adhesive becomes too high, and the workability during coating is remarkably lowered.

  The tackifying resin acts to improve the tackiness and wettability of the hot melt pressure-sensitive adhesive composition and to lower the melt viscosity.

  As tackifying resins, dicyclopentadiene (DCPD) resins and their hydrogenated resins, aliphatic (C5) petroleum resins and their hydrogenated resins, aromatic (C9) petroleum resins and Examples thereof include hydrogenated resins, aliphatic-aromatic copolymer resins, hydrogenated resins, and styrene resins.

  Natural resins include terpene resins and their hydrogenated resins, and terpene-aromatic copolymer resins and their hydrogenated types. One is a styrene resin (A), and the second is a styrene resin. Those having good compatibility with the thermoplastic elastomer may optionally be used alone or in combination of two or more.

  As a preferable tackifying resin, a styrene resin (A) is essential and a hydrogenated type (B) of a petroleum resin is preferable from the viewpoint of compatibility with a styrene thermoplastic elastomer, tack, heat resistance, and hue.

  In the present invention, the tackifying resin used is at least two of styrene resin (A) and petroleum resin hydrogenated type (B), and A has a softening point of 150 ° C. or higher, preferably 150 ° C. or higher and 160 ° C. It is preferable that it exists in the range below ° C. On the other hand, the softening point of B is in the range of 120 ° C. or higher and 140 ° C. or lower, and more preferably in the range of 125 ° C. or higher and 130 ° C. or lower.

  The reason why the range of the softening point of A is narrowed to 150 ° C. or higher greatly contributes to the improvement of heat resistance with the minimum necessary amount. When the temperature is 150 ° C. or lower, the content must be increased, which adversely affects the adhesive performance. The reason why the range of the softening point of B is narrowed is that an adhesive residue is left on the adherend at 120 ° C. or less during peeling under heat resistance.

  The reason why A and B are used in combination is that A alone cannot exhibit adhesive performance, and B alone, on the contrary, remains uneasy about heat resistant performance and cannot suppress temperature dependence as much as possible.

  The compounding quantity of the tackifying resin which comprises the hot-melt-type adhesive composition of this invention is 35 to 65 weight part, Preferably it is 50 to 55 weight part.

  The composition ratio of the styrene resin (A) having a softening point of 150 ° C. or higher and 160 ° C. or lower and the petroleum resin hydrogenated resin (B) having a softening point of 125 ° C. or higher and 130 ° C. or lower is 1/9 to 3 / Is in the range of 7, preferably in the range of 1/4 to 1/3.

  If the compounding quantity of tackifying resin is less than 35 weight part, the adhesive force of a hot-melt-type adhesive composition will fall easily. Moreover, when the compounding quantity of tackifying resin exceeds 60 weight part, the cohesion force of a hot-melt-type adhesive composition will fall easily.

  If the A / B composition ratio is less than 1/9, heat resistance will decrease and problems such as slipping and adhesive residue will occur after heating of the thermal material. If it exceeds 3/7, tack and low temperature properties will decrease, and before heating. Sliding occurs. The plasticizer acts to reduce the melt viscosity of the hot melt pressure-sensitive adhesive and improve the wettability.

  As the plasticizer, paraffinic oil is preferable because of compatibility with the styrene-based thermoplastic elastomer. The blending amount is 1 to 25 parts by weight, preferably 10 to 15 parts by weight. When the blending amount of the plasticizer exceeds 25 parts by weight, the cohesive force of the hot melt pressure-sensitive adhesive composition tends to be reduced, and adhesive residue after the heat generating material is generated occurs.

  The hot melt pressure-sensitive adhesive composition of the present invention includes an inorganic filler, a surfactant, a coupling agent, an antioxidant, an ultraviolet absorber, a light stabilizer, and a colorant as long as the properties as a pressure-sensitive adhesive are not impaired. Such additives can be added as necessary.

  As the antioxidant, a phenol-based, amine-based, or phosphorus-based antioxidant can be used, and the amount of the antioxidant is 100 parts by weight based on the total amount of the styrene-based thermoplastic elastomer, tackifying resin, and plasticizer. The amount is preferably 0.1 to 2.0 parts by weight, and more preferably 0.5 to 1.5 parts by weight. When the blending amount of the antioxidant is less than 0.1 parts by weight, the antioxidant effect is not sufficient and the stability during heating is hardly improved. Moreover, even if it mixes the compounding quantity of antioxidant more than 2.0 weight part, it is difficult to acquire the effect beyond it.

  As the ultraviolet absorber, benzotriazole, benzophenone, benzoate, cyanoacrylate, or the like can be used, and the blending amount thereof is 100 parts by weight of the total amount of the styrene thermoplastic elastomer, tackifying resin, and plasticizer. It is preferable that it is 0.1-1.5 weight part with respect to it, and it is more preferable that it is 0.1-1.2 weight part. When the blending amount of the UV absorber is less than 0.1 parts by weight, the UV absorbing effect is not sufficient, and the weather resistance is hardly improved. Moreover, even if it exceeds 1.5 weight part, it is difficult to acquire the effect beyond it.

  As the inorganic filler, inorganic fibers and inorganic foams such as calcium carbonate, zinc oxide, glass beads, titanium oxide, alumina, clay, ferrite, talc, aerosil, silica and glass fiber can be used. The amount of the styrenic thermoplastic elastomer, tackifying resin, and plasticizer is preferably 0.1 to 3.0 parts by weight, and 0.5 to 1.5 parts by weight based on 100 parts by weight of the plasticizer. It is more preferable.

  As a method for producing the hot melt pressure-sensitive adhesive composition of the present invention, a known heat-melt mixer or the like is used. For example, a screw-like or ribbon-like stirrer / mixer, a kneader, a uniaxial or multiaxial extruder, a mixer and the like can be mentioned. It is preferable to set and manufacture these in a temperature range of 100 ° C to 260 ° C. In order to prevent resin deterioration, production in an inert gas atmosphere such as nitrogen gas is more preferable.

  The thermal material of the present invention includes a general disposable body warmer, but is not limited to this. As a structure, it is the adhesion layer and heat generating body using the adhesive of this invention, and a heat generating body is comprised from packaging materials, such as a film, and the heat-generating composition included in this.

  The adhesive layer is formed by applying an adhesive on a packaging material such as a film constituting the heating element. The pressure-sensitive adhesive layer can be formed on the entire surface or part of the packaging material such as a film constituting the heating element, with a thickness of preferably 10 to 300 μm, more preferably 20 to 200 μm.

  Examples of the application method include a method of applying in stripes or dots, but are not limited to these methods. For coating, a roll coater, a spiral coater, a bead coater, a slot coater, a screen coater, or the like can be used. The coating temperature (° C.) is preferably 90 or more, more preferably 100 or more, particularly preferably 110 or more, and preferably 220 or less, more preferably 200 or less, particularly preferably 180 or less. The adhesive layer may be formed after the heating element is formed or before the heating element is formed. In the latter case, for example, a pressure-sensitive adhesive is preliminarily applied on a film constituting the heating element to form an adhesive layer, which is heat-sealed with a filling machine to form a bag and filled with a heat-generating composition therefor. Can be formed.

  Alternatively, the pressure-sensitive adhesive can be preliminarily applied onto a release paper or another film to obtain a pressure-sensitive adhesive film, which is then pressure-transferred to a heating element to provide a pressure-sensitive adhesive layer.

  A heat generating body is comprised from packaging materials, such as a film, and the heat-generating composition included in this. For example, it is preferable that the exothermic composition is stored in a bag body having at least one side made of a breathable film. As the breathable film, a non-breathable film having a needle-like through-hole or a single-layer or multilayer porous film is used, and a laminate film of a porous film or the like and a nonwoven fabric is also used. Preferably used.

  The non-breathable film may be a single layer or laminated film that does not substantially transmit oxygen or air. Examples of the resin constituting this film include polyolefins such as polyethylene and polypropylene, polyvinyl chloride, polyvinylidene chloride and polyester, and these can be used alone or in combination. In addition, a laminate film of the above film and a nonwoven fabric is also preferably used. The thickness of the non-breathable film is preferably 20 μm to 200 μm, more preferably 30 to 100 μm.

  Any exothermic composition may be used as long as it generates heat upon contact with air, and an auxiliary agent such as saline, activated carbon, water-absorbing resin and / or vermiculite is added to the main agent such as iron powder. Known materials are used.

Claims (5)

  A hot melt pressure-sensitive adhesive composition obtained by blending a styrene-based thermoplastic elastomer with a tackifying resin, wherein the tackifying resin is at least a styrene-based resin with a softening point of 150 ° C. or higher (A), a petroleum resin-based And / or a hot melt pressure-sensitive adhesive having a softening point of 120 to 140 ° C. (B) and a composition ratio of A / B in the range of 1/9 to 3/7.   The styrenic thermoplastic elastomer is 25 to 45 parts by weight, the tackifying resin is 35 to 65 parts by weight, and contains 1 to 25 parts by weight of a plasticizer. The hot melt pressure-sensitive adhesive composition according to claim 1.   The styrenic thermoplastic elastomer is composed of one or more block copolymers containing 10% by weight to 16% by weight of styrene, and has a melt flow rate (200 ° C., 5 kg) of 5 (g / 10 minutes). It is -35 (g / 10min), The hot-melt-type adhesive composition of Claim 1 or 2 characterized by the above-mentioned.   The hot-melt pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the plasticizer is a plasticizer of paraffinic oil. The thermal material provided with the hot-melt-type adhesive composition in any one of Claims 1-4.